The Eminent German-born pianist Egon Petri was of Dutch descent. His father was Henri Wilhelm Petri (1856-1914), a Dutch violinist who served as concert-master in Hannover and of the Gewandhausorchester Leipzig. His mother was a singer. Egon's father taught his son the violin, and the teenage Egon played in the Dresden Court Orchestra (1899-1901) and in papa's string quartet. He also studied organ. At age 7, however, he began piano lessons, notably with Teresa Carreño (Louis Moreau Gottschalk's Venezuelan-born protégé), Buchmayer and Draeske. He also received composition lessons from Kretzchmar. On reaching 20, encouraged by his father's friend Ferruccio Busoni, Petri decided the piano was his lifetime instrument. He became F. Busoni's pupil and eventually his amanuensis. At Dresden, Weimar, and finally Berlin (where Petri also studied philosophy). He learned from F. Busoni not only the art of pianism, but an appreciation of J.S. Bach and Franz Liszt in particular, the twin anchors in his transatlantic repertoire.

Egon Petri launched his career as a piano virtuoso in 1902. Subsequently he toured extensively in Europe. In 1915, F. Busoni retired to Switzerland for the duration of World War I, and invited his favourite pupil to assist him in editing Bach's keyboard works. By this time, Petri had debuted in Holland, Germany, and England, and was professor of music at the Manchester Royal College of Music for six years (1905-1911). In 1920, F. Busoni moved back to Berlin, where the Weimar Republic appointed him professor of composition at the Academy of Arts. When Petri came too, Arnold Schoenberg engaged him at the Hochschule für Musik (1921-1926), where his scholarship students included Gunnar Johansen and Victor Borge, both from Denmark. For many years Petri also taught master-classes at the Basle Conservatory. In 1921, he joined F. Busoni in a concert of two-piano music at London, and in 1923 became the first foreign-born solo artist to perform in the Soviet Union, so successfully that he played 31 concerts in 40 days.

Egon Petri took up the cause of his mentor's music, including the Brobdingnagian Piano Concerto with chorus and orchestra. At the same time he proselytised on behalf of F. Liszt (already out of favour intellectually; his importance and influence were not re-evaluated until after World War II), and Bach of course, in F. Busoni's editions and transcriptions. In 1927, Petri moved to Zakopane, Poland, where he lived until 1939. On January 11, 1932 he made his USA debut in New York, then performed on both sides of the Atlantic until the outbreak of World War II. He also taught at Boston's Malkin Conservatory in 1934-1935.

When World War II threatened, Egon Petri moved to the USA, where he became pianist-in-residence at Cornell University (1940-1946), and then at Mills College in Oakland, California (1947-1957), where Darius Milhaud had been teaching composition since 1941, and John Cage was in charge of piano accompanying. He also taught at the San Francisco Conservatory of Music (1952-1962). Petri's notable American pupils included Earl Wild, who has spoken of his teacher's "quiet tone that was never forced...his playing had a long line instead of stopping to suffer over a phrase."

After World War II, Egon Petri resumed his extensive tours. In 1957, he re-visited Europe for the first time since the War. Finding himself forgotten he returned to the USA permanently. He made his farewell concert appearance in a recital in 1960. As F. Busoni's foremost student, he followed in his mentor's grand manner of piano virtuosity. His performance of J.S. Bach and F. Liszt were formidable. Of Bach he said: “Bach is like an eagle who sets out from a high peak always viewing the goal”. Petri also championed the works of Charles-Valentin Alkan and Medtner as well as F. Busoni